Aircraft power plant supercharger



Feb. 25, 1941. g PRKE;v 2,233,031

AIRCRAFT POWER PLANT SUPERCHARG ER Filed June 13, 1939 4 Sheets-Sheet 1A 9 INVENTOR Feb. 25, 1941. C PRY|CE I v I 2,233,031-

AIRCRAFT POWBR'PLANT SUPERCHARGER Filed June l3, 1939 4 Sheets-Sheet 2 ISECTION 5 I NVENTOR,

Feb, 25, 1941. N. c. PRICE I AIRCRAFT POWER PLANT SUPERCHARGER Fil edJune 1939 4 Sheets-Sheet 4 INVENTOR Patented Feb. 25, 1941 UNITED STATESPATENT OFFICE Nathan C. Price, Seattle,

Corporation,

Wash assiznor to Sirius a corporation or California Application June 13,1939, Serial No. 278,917

IOClalms.

The invention creates more rational methods of inclusion of aircompression and waste heat recovery apparatus in motors. It relatesparticularly to supercharging of aircraft engines and 5 pertainsgenerally to problems connected with the furnishing of atmospheric airto combustion chambers at extremely high altitudes as well as at loweraltitudes. The invention is also useful for operating aircraft pressurecabins which accommodate passengers or freight, and for actuatingaircraft compressed air power systems including de-icer boot systems,aerodynamic surface boundary layer controls, and the like. It embodies aunique method of compressing air for combustion chambers which must becooled.

In addition the invention provides a practical solution for aircraft jetpropulsion schemes. It serves as a mechanism for enabling movement ofaircraft at velocities approaching or exceeding the velocity of sound.

It is an object of the invention to provide an air compressor of minimumweight and complication. Ease of installation and improved reliabilityare likewise sought. To this end, a centrif- 5 ugal impeller, adiffuser, an intercooler, a driving turbine, a vapor condenser, and anair circulator for the condenser are interconnected in novel fashion inan integral unit. The proximity and particular arrangement of theelements composing the unit produce functional relationships in each ofthe elements constituting an improvement in operational efiiciency.

Accordingly the impeller cooperates with a more efficient diffuser,characterized by elimination of turbulence and undue frictional pressuredrop in the air being pumped. Furthermore the diffuser is peculiarlyformed to control the temperature of the air. The diffuser possesses ashape which makes it ideal as a heat transmis- 40 sion surface. Therelatively small and unavoidable skin friction therein serves to promotedesired heat transfer. Therefore the pressure air can be considerablycooled for use in internal combustion engines. The heat from the air isconverted into power for driving the impeller. The reduction ofcombustion air temperature suppresses engine detonation and increasesthe volumetric eificiency of the engine induction system.

Under certain circumstances the heat transfer process in the diffusermay be reversed from cooling to heating of the air, subject to controls.Thus icing conditions in the engine carburetor may be overcome or theengine more quickly started by adding heat to the compressed air.

For further example, the difiuser temperature may be varied, subject toappropriate regulation, increased or lessened to maintain comfortableconditions in a pressure cabin.

It is an objective of the invention to provide 5 a supercharger of moreuniversal use in the aircraft through provision of, special airwithdrawal connections in the supercharger at different pressure andtemperature levels, yet without necessity to resort to duplication ofmoving parts. 19 Relatively high pressure is made available foralimentation of engine combustion chambers. However a part of the air iscompressed only to relatively low pressure for purposes exemplified bycooling of working vapor condensers. These 15 arrangements obviaterecourse to wasteful throttling of the air at the highest pressure levelto a lower pressure level. Accordingly power is saved.

The supercharger of the invention is constructed to provide pressure airat a given temperature level for one consumer and simultaneously at adifferent temperature level for another consumer. Thus cool air may berequired for the propelling engine yet the supercharger delivers warmerair for the pressure cabin or for de-icing boots on the leading edges ofthe wings.

It is a still further objective of the invention toprovide asupercharger which is capable of independent operation. Accordingly thesupercharger can start the main propulsion engine by pumping heated andcompressed air into it. The air being delivered. from the superchargermay be maintained at a comparativelyhigh temperature during the warm-upperiod to reduce the length of time required to prepare engines forflight.

It is an objective of the invention to supply an all-purposeaircompressor for aircraft systems, which is capable of functioning duringinactivity of the aircraft propulsion system, yet which recovers wasteheat from the engine when the aircraft is being propelled.

It is desired to provide a supercharger for aircraft which considerablyimproves the efliciency of the power plant as a whole, and which reducesaerodynamic drag, in particular the parasite resistance ordinarilyincidental to accomplishing the cooling of the aircraft engine.

It is a further objective to supply a supercharging system having themost emcient flow passages consistent with effective transmission .ofheat to or from the compressed air, and to include the most eflicientstructure for instrumentalities involved in operation of the impeller.

efficiently propelled at all speeds up to the maximum. Arrangements arealso provided for transition of the propulsive thrust effort from ascrew propeller to an exhaust gas jetin order to enable continuousflight under power from sea level up to the stratosphere, andfrom astandstill up to the velocity greater than that of sound.

With these and other objectives in mind, as

will appear hereafter, my invention comprises the novel parts and thenovel arrangement thereof relative to the aircraft and to the aircraftpower plant.

Figure 1 diagrammatically represents a section of a typical form of thesupercharger along the central axis thereof.

Figure 2 is a schematic representation of transverse sections of thesupercharger of Figure 1 viewed from the air inlet end.

Figure 3 is a perspective view of a fragment of the combined diffuserand temperature conditioner of the supercharger.

Figure 4 is a perspective view of a fragment of the condenser coreemployed in the supercharger unit.

Figure 5 is a schematic representation of the iiow control arrangementassociated with the installation of the supercharger in conjunction withan aircraft engine and an aircraft pressure cabin.

Figure 6 is a diagrammatic representation of the supercharger installedin an aircraft adapted for operation in the stratosphere at extremelyhigh velocity.

Figure 'I is a representation of an installation of the supercharger inconjunction with an aircraft .power plant adapted for high altitudeoperation at high speed.

Figure 8 reprwents an end view of the internal combustion enginecooperating with the supercharger to propel the aircraft shown inFigures 6 and '7.

In Figure 1 air is compressed in a supercharger unit I00 by acentrifugal impeller I having a number of radial blades 2, a conical hub8 with apex pointed downward, and a driveshaft 30 extending upward alonga principal axis A of the unit I00. The air is first compressed to arelatively small extent by curled lips S at the lower edges of theblades 2 adjacent to an axial inlet 0 at the bottom of the superchargerunit, as the impeller rotwtes at high speed and scoops the air. Aportion of the indrawn air flows from the lips I in a generally axialand somewhat radial direction about the surface of the hub 0 into anannular discharge orifice 4 between the inner diameter of an annularbacking plate 0 and the greatest diameter of the hub 0.

The plate 5 serves to support .the upper edges of the outer portions ofthe blades 2. Each blade 2 forms a spoke 2' between the hub I and theplatel. Air supplied to the orifice l is driven upward into the spacesbetween radial diffuser vanes 0 arranged at the entrance of an annularduct 22 which is coaxial with the shaft 30. A comparatively' lowvelocity is imparted to the air flowing adjacent to the hub I, thereforeonly a relatively small pressure rise is produced in the air beyond thatalready caused by the lips 8 as the air deoelerates between the vanes 0.In a representative case the air in the inlet 9 may be at a pressure of.3 of an atmosphere and at a temperature of 0 degrees Fahrenheit, but inthe duct 12 it will exist at a pressure of .4 of an atmosphere and at atemperature 40 degrees Fahrenheit.

' The air in the duct 22 is in a condition suitable for extraction ofheart from a condenser core. as will be described later. However theremainder of the air drawn into the impeller is to be compressed to afar greater extent, to 1.1 atmosphere pressure for example, foralimentation of a power plant and a pressure cabin. To this end the airis permitted to flow radially outward between the blades 2 wherein itgains high tangential velocity and further compression. The air isreleased from the periphery of the impeller i into a toroidal diffuser84 which commences in the plane of the impeller but which curves upwardabout a hollow tubular ring I4 directly above the periphery of theimpeller. The ring has a pitch diameter approximately equal to thediameter of the impeller. The upward change of direction of the airwithin the diffuser 8! is aided by the presence of an annular turningvane I! generated radially and spaced from the ring about half waytoward a circular bottom plate 13 of the supercharger. The plate 13bounds the lower side of the impeller and is provided with externalradial stiffening ribs 14 extending from the inlet 9 outward to a flangeH of the plate, which serves as an attachment to a flange 03 of a barreli5 encompassing the diffuser Bl.

The lower end of the shaft 39 is supported within a hollow spindle 31 bya ball bearing 42 and the upper end by a ball bearing 30. Between thebearings is an annular space 40 which serves as a storage space forlubricant. A cap 13 locks the bearings axially within the spindle 31. Aconical shell 00 supports .the base of the spindle and forms an innerboundary for the flow of air between the vanes 8 in cooperation with acoaxial conical shell 91 which acts as an outer boundary.

An upper end 24 of the barrel 15 is invaginated as a tube 2| which joinsthe shell 81. The vanes 0 form bridges between the shells 96 and 91,completing the support of the shaft 39 in the barrel 15. The spindle 31extends upward from the shell 98 into a conical turbine wheel 34 of aturbine 02. The apex of the wheel has an inwardly directed hub 35 whichengages a spline 30 above the bearing 38 and on the shaft 39. Thedescribed supports for the impeller I and for the wheel 3| are ideallysuited from the standpoints of compactness, durability, andnon-interference with the various passages conducting air or workingfluid.

The compressed air from the diffuser 84 is collected in an annularchamber 51 of the barrel 15 after having swept a pack of heat conductiveribbons I0 attached to some heat exchanger tubes 20 in the lower .partof the chamber. The air is delivered from an outlet 12 to the engine orto other consumers. The temperature of the air in the chamber Bl may beat about 300 degrees Fahrenheit by virtue of the hyper-adiabaticcompression which occurs in .the impeller and diffuser, or on the otherhand at about only degrees Fahrenheit due to heat liberation in thediffuser, as will be described.

The temperature of .the air at the inlet 0 is ordinarily raised from aconsiderably lower atmospheric value by ramming action in a scoop 2Hexposed to the air flowing about the aircraft and feeding the unit I00,as illustrated in Figures 5 and 6. Thus, in the exemplary case, thepreviously cited air conditions at the inlet 9 may resuit from flight at650 miles per hour at 40,000

asaaosi. o

altitude, where the air temperature is lower r minus 60 degreesFahrenheit and the pres- .2 of an atmosphere.

1 a conical turbine casing sursome buckets titof the turbine A nozrlrs 1is attached to the lower and smaller e casing and is enclosed in anannular encompassed by a coarn'al tube 23 which is upward from the shellthe tube 26 define the annular estrain the air to how to a region ectionof motion of the air becomes cooling then passes over the end ouiar ductbetween a coaxial inand a cylindrical condenser 99. Li distributes theair to the spaces ioetransverse fins of a helical tube t l about thesides of the condenser Sub the air flows radially inward to a centhroughinterstices in the condenser. e of the cup joins a flange ill the barrelSome longitudinal extend from the flange to vapor, such as steam at apressure of and at a temperature of 906 lr nheit for example, admittedto and passes through buckets causing the turbine to drive the imue tothe shape of the wheel 36, the from the turbine a substantially spaceand is then guided by a by a central cone into numerthe condenser Thevapor flows d along the slots to a crown chamber which point the vaporis nearly or comccndensed at a temperature of 150 de- .hrenheit, forexample. Thence the con- .te flows downward in the tube to a transibewhich feeds a pump til mounted in e cone 28. The condensate, cooled todegrees Fahrenheit for example, is forced by the pump along a transfertube 27 and through a manifold ili to the tubestt, wherein it becomesreheated, and finally is collected in a manifold to be directed into thering It, where it attains a temperature of 260 degrees Fahrenheit forexample. The condensate is discharged from the ring it and from the unitHill through an outlet 28.

The pump Elil is rotated by a drive shaft I"! connected to the pump isadvantageously located in the cone 28, because it is swept by coolingair in the bore 55 and therefore is effectively cooled to preventvaporization at its inlet. Furthermore, the location of the pumpopposite the bottom and along the axis of the condenser 99 permitsliquid to be drained from the condenser under all conditions of flight.Ordinarily during level flight or especially during pull out from adive, there will be a positive head of condensate in the tube 5 3tending to prevent cavitation or vapor-lock at the pump inlet. Evenduring inverted flight the pump is so positioned that it can draw allthe condensate from the condenser without vapor-lock resulting, becausethe distance through which the condensate must be lifted is small.

craft will also be unable to cause vapor-lock to occur because of thecentral position of the pump. Thus the particular placement of the pump,assisted by cooling from the condenser air, insures reliable operationof the pump at all times. An

upper end of the shaft 39. The I Lateral or fore and aft acceleration ofthe air-' auxiliary drive is projected from th the pump along the axisa.

In order to facilitate disassembly of te unit ltd, the diffuser isjoined -e ea n and to a flange ll of the tube by a resil ring Thereforethe condenser assem c be lifted from the barrel following c nection ofthe flange from the f A circumferential shoulder of the shell ii'l withthe tube cl wardly projecting web of the lb of the ring it acts as an aicooperation with the plate enclosed by the ring it forms channel of highvelocity, to improve the heat transmission between the air.

The uppermost sector of Figure 2 illus fragment of the impeller i, thediffuser a section 8 of the barrel viewed from h with the plate itremoved. The numerous ly spaced diffuser vanes it are formed as platesgenerating tangentially from the pe i of the impeller in a directioncorrespc' the direction of rotation of the i vanes ii tend to becomerachal the axis A as they become more 6 impeller, therefore in orderthat air tain its filamentous flow in the increasing g between thevanes, some inter-vanes are inserted C adjacent to the turning vane asshown at it.

The vanes ii and are bonded to the ring and to the turning vane so thatin addition to converting air velocity head into pressure head, heat isconducted at a high rate from the air into the fluid contained in thechannel The diffuser 8 3 is highly efficient from the standpoint ofcompression, because the air is guided by many thin walls to preventturbulence. Furthermore the air is closely controlled by the describedstructure and the divergence between the vanes and the curvature of thevanes can be made more abrupt so that the space requirements of thedifiuser are relatively small. The numerous thin vanes embody ideal heattransfer surface for delivering heat of air compression into the ringid. Even unavoidable skin friction in the diffuser serves the usefulpurpose of producing heat transfer. However the viscosity of air isroughly proportional to the temperature and this effect results inreduction of boundary layer friction in the diffuser, because thediffuser vanes are cooled by condensate. As a consequence the efliciencyof the diifuser is appreciably improved.

The next lower sectors of Figure 2, designated as sections T and U ofFigure 1, illustrate the vanes of the diffuser M in transverse sectionat the plane of the ring it, and portray the arrangement of the heatconductive ribbons I9 in thermal contact with the helical tubes 20.

Figure 3 illustrates the latter construction more precisely. The ribbonsl9 comprise folds of thin metallic strip attached laterally andtransversely to the side of the tube ends of the folds to form somejoints 52 conforming to the circular shape of the tubes 2!). Partiallycooled air from the spaces between the vanes H and 12 passes between thefolds of the ribbon l9, as represented at 19. At 80 the condensatewithin the tube 20 is required to pass in heat transferring relationshipwith some radial lands 6| on the inner surface of the tube 20, which arehelical as at 90.

Details of the condenser 99 are revealed in Figure 4 and in the lowestsector of Figure 2,

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designated as section V of Figure 1. The path of flow of the cooling airbetween some transverse flns 65 formed about the slots 55 is representedby 16. The edges of the fins 65 adjacent to the bore 56 merge intoupturned flanges 64 to direct the air upward and out of the bore 56.Some alternate flns 66 between the fins 65 have the inner diametersslightly larger than those of the flanges 64, in order to provide a moreuniform flow passage and less restriction adjacent to the flanges 64.The flow of working vapor being condensed in the slots 55 is representedat 65. The slots 55 are defined by flattened tubes 61 and 66 alternatingrespectively in radial width with regard to the axis A, in order toprovide a more uniform passage area for the cooling air and to preventthe velocity of the cooling air from being un'duly increased as itbecomes heated. Numerous wavy strips 63 are directeed axially along theslots 55 and bridge the relatively narrow tangential width of the tubes61 and 68. The presence of the strips 63 considerably increases the areafor heat transfer from the exhaust working vapor to the tubes 61 and 66,and the undulating form creates turbulence, which increases the heattransmission.

Generally, the conduits handling working fluid, such as the ring H, thetube 20, or the tube 56 are constructed from relatively hard corrosionresistant metal, such as an alloy of copper and nickel.

However the vanes II and I2, the ribbons I9, the flns 53, and the flns65 and 66 are preferably constructed from an alloy of comparatively highthermal conductivity, such as copper combined with small quantities ofsilver and chromium, and bonded to their respective tubes by welding ina controlled atmosphere furnace.

In accordance with the foregoing illustrations, the exhaust workingvapor issuing from the turbine 82 is directed intopassages of relativelygreat heat absorptive properties, yet with a minimum of wasteful flowresistance, inpart befat cause the passages generally conform to theshape of the body of vapor flowing from the turbine at high velocity. Ithas been found that the passages provided for the cooling of the workingvapor in the core have a high rate of heat dissipation in comparisonwith their frictional pressure drop. Upon reaching the upper end 58 ofthe condenser the vapor is nearly condensed, and may then flow down thetube 54 to be cooled well below the saturation temperature.

The condensate, cooled to 60 degrees Fahrenheit for example, isappropriate for absorption of heat in the intercooler and diffuser. Theillustrated arrangements permit a recovery of heat ordinarily lost fromthe air being cooled, and this recovery is accomplished with completecounterflow and minimum frictional pressure drop being imposed upon thepressure air. The compressed air is discharged from the intercooler intoa space which is properly adapted to collect the air and to deliver itto the consumer.

Ordinarily in aircraft the intercooling of supercharged air involves theuse of bulky passages for the cooling air and it is furthermoredifficult to bring the cooling air to these passages. On the other handit is also inconvenient to divert the compressed air to a remotelyplaced intercooler. In ordinary supercharger installations seriousaerodynamic drag is involved in forcing cooling air into the intercoolerand it is not practical to combine the intercooler with the diffuser,because of the bulkiness of the spaces required for cooling air. Theseserious disadvantages are eliminated by the invention.

In Figure the tube 26 is subdivided into a region 20a, which affects thetemperature of the air being supplied to the outlet 12, and into aregion 20b, which affects the temperature of the air being supplied to aduct Ill connected to a pressure cabin 2l6. Ordinarily the outlet I2'supplies an engine combustion chamber and therefore a thermal device,such as an ice indicator 3 which can sense ice formation in the engineinduction system, is exposed to the outflow. This arrangement or othersuitable mechanism may be employed to position a three-way valve 306through a system of interconnecting links including a tie rod fllii, abell crank 305, a tie rod 368, and an arm 36'Iin order to control thetemperature in the region 2611. The valve 306 communicates with a duct305 bleeding relatively hot exhaust vapor from the turbine 52 and alsoregulates the flow of relatively cool condensate from the tube 21 intothe region 260.

Accordingly, if ice is indicated at 3 or if a deficient temperature issensed, the exhaust vapor is allowed to bypass the condenser 98 by meansof the duct 305 and to pass along the region 200. to become condensed byheating of the engine air. The condensate is then withdrawn from theregion 26a by a pump 23! connected to the outlet 26. The exact form ofthe indicator 3 is immaterial to the invention and such indicators arecommonly used.

A thermostat 3l5 in the cabin 2 l6 actuates another three-way valve 3|!located at the Junction of a duct 3 with the ring 20, by means of a tierod 3 and an arm- 3l3. If the cabin temperature is subnormal, the valve312 admits relatively hot vapor from the turbine 82 along the duct 30!to the region 20b. The vaporbecomes condensed as it heats the air beingsupplied to the pressure cabin and is finally discharged as liquid intothe outlet 26.

If the ice indicator 3 senses no ice formation tendency or if thethermostat 3l5 senses excessive temperature in the cabin, the valves 36!and 3I2 become rotated by their linkages to reduce the flow of hot vaporinto the regions 26a and 20b respectively.

If the valves 306 and 3|2 have been rotated far enough to close off theducts 3M and 305, relatively cool condensate is admitted from the tube21 into the regions 20a and 20b to absorb heat from the compressed air,thereby achieving heat utilization and reducing the temperature of theair supplied to the engine and to the pressure cabin. It is obvious thatthe valves 366 and 3!! operate entirely independently subject to theirautomatic controls and through an infinite variation of openings tomaintain desired conditions in the engine air or in the pressure cabinair. In addition, the controls may be manually biased through the knob33!! attached to the bell crank 308. Accordingly the operator of theaircraft may vary the temperature conditions imposed upon the engine.Thus the engine may be heated, in order to reduce the length of itsstarting period.

The valves 306 and M2 are capable of completely sealing of! the flowfrom the pump 36 into the tube 20 and therefore some serial ducts 3l6and 320 are brought into communication between the tube 21 and theoutlet 26. A back-pressure valve M5 is included between the ducts 3l6and 320. The valve 3l9 comprises a ball 311 forced against the duct M6by a spring 318, so that positive pressure exists at all times withinthe tube 27, yet liquid may escape from tube at when the valves tilt or3i? isolate the tube ill trom he regions Ella and some radial walls tileand iltd in the space b tween the tube 2i and the barrel separate thecompressed air for the engine from that for the pressure cabin.

The pump 723i is driven by an aircraft propulsion engine tilt. Thedischarge from the pump Elli enters the engine where cools the a gine byabsorption of heat. According ing vapor issues from the engine along aduct 383 to a throttle The throttle is employed for regulation or theflow of we g vapor along an inlet-tube to the turbine thereby acjustingthe rate of speed oi the s cercharger to control the power developed inthe engine.

The separately fired boiler all connected in parallel to the enginecooling to generate working vapor from condensate bled from the outletby a duct 3 b. The vapor so formed is delivered along a duct to thethrottle ti. Thus the turbine 52 can operate by waste heat recoveredduring power op eration and can be revolved by workin vapor from theboiler 3M when th engine is not in operation.

Figures 6, 7, and 8 illustrate a radi Elli), which includes eightcylinder .i mounted upon a cylindrical crankcase hav ing an axis B. Fourexhaust manifolds are located between alternate pairs the banks 2S2.Four air induction manifolds are positioned between the remaining pairsof the banks iltil. This form of engine lends itself particularly tocompact installation with the super-- charger unit in a conoidal fairingextending rearward from the pressure cabin As shown in'Figures s and thesupercharger unit lfill is preferably placed between the engine 280 andthe pressure cabin with the axis A normal to the axis 13. Exhaustcooling air from the condenser is expelled rearward at the outsidesurface of the fairing 231 from a nozzle H3. A propulsive jet 255 issuesfrom the nozzle 2m.

In Figure 7 the compressed air from the supercharger outlet 72 istransferred into the induction manifolds 203 by a quadruple distributorduct 220. The engine exhaust four rearwardly directed nozzles Ell whichare attached to the ends of the manifolds and which protrude throughcut-out portions 25322 in the fairing 201. Propulsive exhaust jets tillare produced at the nozzles 286.. A drive shaft @935 along the axis Benters a gear box 22? for driving some hubs 208 and M2 or counterrotating propellers 209'and 2| l, at the terminus of the fairing 201. InFigure 6 the somewhat modified installation involves the transfer of thecompressed air from the outlet 72 into a second stage enginedrivensupercharger 219, along a duct m6. The supercharger 2| 9 is attached tothe rear of the crankcase 205. The distributor duct 22b extends from theperiphery of the supercharger m.

In the installation represented by Figure '7 the accomplished throughthe propellers 209 and 2| 1, but at higher altitudes and duringincreased aircraft velocity the propulsive eifect of the nozzles 206 maypredominate.

The installation represented by Figure 6 is adapted for extremely highvelocity at high alsystem, in ordergas issues from heat conversion gigconnected. era the "opeller and the propeller retracted stream, thespeed engine increases considerably due to the absence or" torquedelivery to the propeller. lice the induction and the rate flow greatlyincrease and the jet propulsion ei Delayed conine tmder this conditiondisadvantageous because the rect becomes ustioo. int 2 high not exhaustgas is dellveret "cm the manifolds into an Cfliitfifiilul tubecomlcustio more pronounced.

ay be completed prior to a rear= wardly pulsive nozzle at the terminusrig Some pro ea 2? are mounted upon a toroidal hub ate out the axis g oe .i o I 0 directly behind. the

- 24cc sui sends the tube r dameter by some pinsome shafts extend e enes parallel to the J). Eur at vely low altitude the power vets thelarger portion of its pr pulsive thrust through the lola'des .225, butas the tude and spec increase the blades to be corn iehieient and mayabsorb rather Under the latter condition comes highly effective as aTherefore knob tilt is operator or by suitable controls to de-clutch theengine from the blades The mechanism for acccrnplisl'iing this includesa bell cranl: attached to the lcnob deli and having a tab Gilt, whichcooperates with a block itl on the shafts to force the pinions 22$toward the axis B and out of engagement with the hub 228. Then theblades 228, which are pivotally mounted upon the hub by sometangentially disposed pins are no longer held in the plane of rotationby centrifugal force and therefore are blown backward by the atmosphericair into the position indicated by 22% which generally conforms to theshape of the fairing 26? oilering no parasitic resistance to motion ofthe'aircraft at extremely high velocities.

During the jet propulsion the speed of the aircraft may be varied bychange of engine speed, which in turn controls the rate of flow ofexhaust gas. The degree of super-charging is a function of the wasteheat available in the engine and this heat tends to be present in aquantity proportionate to the exhaust gas output of the engine. Heattransmission in the engine is a function of the rate of flow ofcombustibles through the cylinder banks. Accordingly the processes inthe supercharger unit consume the heat dissipated from the englue andthe quantity of heat tends to approximate the supercharging power.requirements.

I claim:

1. An aircraft supercharger comprising a rotary air impeller, a shaftforsaid impeller, a turbine for driving said shaft, a toroidal airdiffuser for said impeller, said diffuser being the nozzle 222bepropulsive method,

die

gas

which the actuated by the aircraft a Oil , impeller at' one composed ofclosely spaced plates, a toroidal condenser core for waste vapor joinedto said turbine, said core having longitudinal tubes communicatlng withsaid turbine and generally radial interstices for passage of coolingair, a region of said impeller containing air at relatively lowpressure, and an air discharge duct extending from said region to saidinterstices.

2. A supercharger as defined in claim 1 and further characterized bysaid tubes being relatively narrow in a tangential direction withrespect to said core and relatively wide in a radial direction withrespect to said core, and spaced strips extending longitudinally withinsaid tubes and being thermally bonded to said tubes.

3. An aircraft supercharger comprising a generally cylindrical casinghaving an air inlet adjacent to one end thereof and a dischargeconnection for compressed air in said casing, an axial shaft enclosedwithin said casing, a centrifugal air impeller fixed to one end of saidshaft adjacent to said inlet, means for driving said shaft, a toroidalcore lying adjacent to the periphery of said impeller, said core havingspaced plates forming a communication between said impeller and saidconnection, a conduit thermally bonded to said plates, and means forforcing a fluid at a temperature differing from that of the air beingdischarged from said impeller along said conduit.

4. A supercharger for a space in a high altitude aircraft, includinggenerally coaxial elements comprising a rotary air impeller, a shaft forsaid impeller, a toroidal air difluser adjacent to the periphery of saidimpeller, a turbine for driving said shaft, anexhaust vapor condensercore joined to said turbine, a generally cylindrical casing encompassingsaid elements, an inlet aperture in said casing for supplying saidimpeller with air, a pressure air outlet connection in said casingcommunicating with said diffuser, a waste air spill in the end of saidcasing communicating with said core, interstices for cooling air in saidcore, a region of said impeller containing air at relatively lowpressure, an air discharge duct extending from said region to saidinterstices, a central recess in said core forming acommunication'between said interstices and said spill, a conduit in thethermal contact with said diffuser, a pump located at said recess, saidpump forcing condensate from said core along said conduit, and a driveextending from said turbine to said pump.

5. An aircraft supercharger comprising a generally cylindrical casing,generally coaxial elements encompassed by said casing including a shaft,a journal for said shaft, a wall for supporting said journal in saidcasing, a rotary air end of said shaft, a conoidal turbine wheel at theother end of said shaft and having an apex pointing away from saidimpeller, a working vapor exhaust chamber adjacent to said apex, aninlet aperture in said casing for supplying air to said impeller, acompressed air outlet in saidcasing, a toroidal condenser core for saidturbine lying adjacent to said chamber, said core having longitudinaltubes for exhaust vapor extending from said chamber and transverseinterstices for cooling air, an air diifuser in said wall, and anannular flow space for air from said diffuser encompassing said turbineand communicating with said interstices,

6. A supercharger for use in conjunction with a high altitude aircraftengine, comprising generally coaxial elements joined together as a unitincluding a rotary air impeller, a toroidal air diffuser for saidimpeller composed of closely spaced plates, a toroidal conduit inthermal contact with said plates having an inlet and an outlet, and aturbine for driving said impeller having an admission and an exhaustend, a vapor condenser joined to said exhaust end, a condensate ductleading from said condenser to said inlet, a working vapor supplyconnection communicating with said turbine, a region of said impellercontaining air at relatively low pressure, and an air discharge ductextending from said region to said condenser.

7. An aircraft supercharger comprising generally coaxial elementsincluding a rotary air impeller, an annular pressure air duct includingclosely spaced fins communicating with said impeller, an annular coolingair duct encompassed by said pressure air duct, a turbine for drivingsaid impeller encompassed by said cooling air duct, a working vaporcondenser having an air swept portion and a vapor swept portionconnected to said turbine, said cooling air duct f orming acommunication between said impeller and said air swept portion, atoroidal condensate duct in thermal contact with said fins, and saidvapor slwept portion being connected to said condensate uct.

8. A supercharger comprising generally coaxial elements including, arotary air impeller having a hub and generally radially disposed airimpelling blades, an axial air inlet at one side of said impeller, ahigh pressure air outlet at the periphery of said impeller, a lowpressure air outlet at the opposite side of said impeller relativelynear the axis of said impeller, a turbine adjacent to said low pressureoutlet for driving said impeller, a working vapor condenser attached tosaid turbine, and a duct connecting said low pressure outlet to saidcondenser.

9. A supercharger for a space in a high altitude aircraft, includinggenerally coaxial elements comprising a rotary air impeller, a shaft forsaid impeller, a toroidal air diffuser adjacent to the periphery of saidimpeller, a turbine for driving said shaft, an exhaust vapor condensercore joined to said turbine, a generally cylindrical casing encompassingsaid elements, an air inlet aperture in said casing adjacent to saidimpeller, a pressure air outlet connection in said casing communicatingwith said diffuser, a waste air spill for said core in said casing,interstices for cooling air in said core, a toroidal conduit in thermalcontact with said diffuser, said conduit being con nected to said core,a region of said impeller containing air at relatively low pressure, anair discharge duct extending from said region to said interstices.

10. A supercharger for a space in a high altitude aircraft, includinggenerally coaxial elements enclosed in a generally cylindrical casingcomprising a rotary air impeller, a toroidal air diffuser adjacent tothe periphery of said impeller, a turbine for driving said impeller, atoroidal conduit in thermal contact with said diffuser, a condenser corejoined to an end of said turbine, a working vapor flow course beingserially extended through said conduit, said turbine and said core, aregion of said impeller containing air at relatively low pressure, andan air discharge duct extending from said region to said core.

NATHAN C. PRICE.

